Keratin-containing fibers are understood in principle to mean all animal hair, for example wool, horsehair, Angora hair, fur, feathers, and products or textiles manufactured therefrom. However, the keratinic fibers are preferably human hair.
The dyeing of keratinic fibers, for example human keratin fibers, generally takes place using coloring compositions which, in addition to other components, contain oxidation dye precursors, in particular oxidation bases (“developers”). After addition of an oxidizing agent as part of an oxidative condensation, these colorless or weakly colored substances react to form dye molecules. For shading the colors thus obtained, a second group of oxidation dye precursors, the so-called couplers, are generally added to the developers. A large number of different tints can be achieved by combining developer and coupler components.
In addition or as an alternative to the above-mentioned oxidation dyes, keratin fibers are dyed by means of direct dyes. These direct dyes are colored molecules that attach to the surface of the keratin fibers.
The coloration of the keratinic fiber obtained by oxidation dyes or direct dyes fades due to external influences such as light, but in particular due to repeated hair washing.
To improve the color retention of oxidatively dyed keratin fibers, the use of zinc salts, for example, is proposed in European Patents EP 1 915 981 B1 and EP 1 923 042 B1. According to the teaching of these documents, the zinc salts are applied to the keratinic fibers after completion of the dyeing process.
However, the color retention values achieved according to the teaching of these documents are not satisfactory in every case.
In summary, there is therefore still a need for methods for improving the color retention of dyed keratinic fibers. Against this background, it has been determined that improved color retention can be achieved by treating keratinic fibers with a combination of specific polymers.
Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.